Recording Multiple Inputs Over the 'Net?

TFGeditor asks: "Thanks to the advice of fellow readers from a previous Ask Slashdot, I now have a PC system optimally configured to produce professional on-air radio programs. Now I have a new problem: my radio co-host and I are in different cities located a few hundred miles apart. In order to give the show a real-time (i.e. 'live') sound, we need to somehow connect us so that we can produce a show complete with co-host banter, real-time interaction, and so on. I want it to sound as if we were both in the same studio. How can we do this? Will Skype or other VOIP applications do this without the result sounding 'tinny' (like a phone connection)? Are there other apps that will do a better job?"

POTS?

[oyenstikker]

Get a phone with an audio out, plug it into your soundboard/computer, and call him up.

Re:POTS?

[Spazmania]

Sure, because a 4khz bandpass filter sounds fantastic.

ISDN

[Ubertech]

This may bust your budget, but there are many radio hosts at commercial radio stations who use ISDN lines back to the studio. The digital voice signal is good enough to make the remote broadcaster sound like they are in studio.

I'm sure there is a better, cheaper digital solution out there. Just make sure you have the bandwidth to handle it.

Depends how much you want to spend.

[Thumper_SVX]

If you are really serious about making it sound "professional", then you'll have to be "professional". This means (ideally) a dedicated link between the hosts.

I listen to This Week in Tech (twit.tv) every week and they encounter the exact situation you have. The way they deal with it is either with Skype (which sometimes causes breakup of one of the hosts due to lag or traffic), or they use an ISDN connection. The ISDN is the best "pro" solution because it allows good quality audio to be passed across a digital point-to-point connection. No lag, no problems. The only problem is that relatively speaking the ISDN is slow and expensive. However, if you want a reliable, lagless P2P connection there's really no better solution for the cost... your next option is a point-to-point frac T1 which can get really expensive. Of course, it depends on the amount of bandwidth you intend to use.

I do some part-time work in a recording studio where often a member of a band is "remote" (or in one case, none of them live in the same cities). Since we're talking multiple high-bandwidth streams the studio actually has several P2P T1's. The results can be awesome as we get real-time audio down the pipe at very high bit rates and resolutions... and the recording can be mixed in real time just as if the band members were there.

Body language might be a loss though. ISDN is good when you're pushing high-quality audio... but you won't be able to get video down that pipe as well. The best way I can think to deal with it is to use two connections; an ISDN for the audio and use an Internet connection with a webcam so you can each see the body language of the other. It'll isolate the traffic so that they're not tripping over one another, and the video feed seems to be the one you can most afford to lose (due to latency, lag, packet drops and so forth).

I wouldn't recommend trying to do a solution across the Internet unless you can live with an occasional dropout.

Also realize that if you're creating either terrestrial radio or podcasts, you have a certain amount of leniency since the quality is lower by default than HD Radio or Satellite. I'm all for spending what it takes... but there's no need to spend more than you need.

Finally, realize also that no matter what the final bitrate and quality of your finished product, the higher fidelity the original streams you mix together, the better. Higher bitrate and quality will give you "headroom" for compression.

Think outside the box...

[tchuladdiass]

If you are only going for the live "sound", but aren't actually broadcasting it live, then you've got a simpler solution. Use whatever quality link you can put up with when talking to your co-host, but don't use that link's output in the final production. Instead, have your co-host also record his session from his end at a higher quality (with only his audio, not yours), and stitch the results together afterwards.

Re:Think outside the box...

[HTH NE1]

Well, still record the crappy audio. It will help to synchronize the separate tracks.

When I edited together a two-camera wedding shoot to DVD for a friend, the cameras didn't have the same timecode, and one of them had to change tapes frequently. I used their on-board audio to sync the images together, then another audio recording from the sound system to replace that (which had to be rate-adjusted due to it being just an audio cassette, so having the camera audio helped to establish sync).

If the cameras had their internal mikes disabled and recorded no audio, it would have been hell trying to get lip sync right. For a non-video podcast, you still want to keep the conversation's timing close to correct.

Record seperately

[Dmala]

If you both have decent recording capabilities, the best way to sound like you're in the same studio would be to each record your own track. Talk to each other over the phone or VOIP or whatever using a headset, but also speak into a decent quality mic, recording locally. When you start, send a couple of blips over the phone and make sure it gets recorded on both systems, so you have a reference point to sync the files up later. When you're done, just have him send you his file. Load both files into an audio editor, line your blips up to sync them, and you should be good to go.